[patch 21/88] x86, setup: mark %esi as clobbered in E820 BIOS call

[Greg KH]

2.6.28-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Michael K. Johnson <johnsonm@xxxxxxxxx>

upstream commit: 01522df346f846906eaf6ca57148641476209909

Jordan Hargrave diagnosed a BIOS clobbering %esi in the E820 call.
That particular BIOS has been fixed, but there is a possibility that
this is responsible for other occasional reports of early boot
failure, and it does not hurt to add %esi to the clobbers.

-stable candidate patch.

Cc: Justin Forbes <jmforbes@xxxxxxxxxxx>
Signed-off-by: Michael K Johnson <johnsonm@xxxxxxxxx>
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx>
Signed-off-by: Chris Wright <chrisw@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
 arch/x86/boot/memory.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/arch/x86/boot/memory.c
+++ b/arch/x86/boot/memory.c
@@ -27,13 +27,14 @@ static int detect_memory_e820(void)
 	do {
 		size = sizeof(struct e820entry);
 
-		/* Important: %edx is clobbered by some BIOSes,
-		   so it must be either used for the error output
+		/* Important: %edx and %esi are clobbered by some BIOSes,
+		   so they must be either used for the error output
 		   or explicitly marked clobbered. */
 		asm("int $0x15; setc %0"
 		    : "=d" (err), "+b" (next), "=a" (id), "+c" (size),
 		      "=m" (*desc)
-		    : "D" (desc), "d" (SMAP), "a" (0xe820));
+		    : "D" (desc), "d" (SMAP), "a" (0xe820)
+		    : "esi");
 
 		/* BIOSes which terminate the chain with CF = 1 as opposed
 		   to %ebx = 0 don't always report the SMAP signature on


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